The present invention relates generally to means for controlling and regulating the delivery of water to a soil environment containing growing plants, as a function of the humidity or moisture in the soil. More particularly, the invention relates to a method and self-contained apparatus for controlling the relative humidity of a soil environment at a pre-set value.
It is common horticultural practice to grow ornamental plants as well as seedlings and cuttings of forest and agricultural species in containers of natural or artificial soil, either outdoors, in greenhouses or hot-beds or indoors. Such potted plants require varying amounts of watering depending on numerous factors such as type of plant, rate of growth, relative humidity and rate of air flow around the leaves, and drainage through the container soil.
Where water supplies are plentiful, sprinkling or hosing from above the plants on some regular basis with sufficient excess to permit runoff usually provides a convenient means for meeting the needs of a group of plants outdoors or in a greenhouse or hot-bed. However, increasing concern for conserving water resources makes this a less than ideal practice.
Indoors, however, where runoff of excess water poses housekeeping problems, it is necessary to carefully water potted plants individually and manually. The chore is onerous and can easily lead to over- or under-watering to the detriment of the particular plant.
In field planting, especially in arid regions where the soil is often highly and variably porous, the terrain uneven, the temperature high and air humidity low, water losses due to evaporation and gravitational seepage from soil volumes well removed from the root systems can far exceed water lost by transpiration from crop foliage and be highly variable from plant to plant. Hence, valuable water supplies which might otherwise cost-effectively support agriculture, often fail with classical irrigation techniques or even with the most advanced trickle irrigation technology.